HMGN5, an RNA and Nucleosome binding protein required for chromatin de-condensation and gene activation [CLIP-seq]

HMGN5 is a member of the HMGN family that de-compacts chromatin and regulates gene expression. Chromatin-associated RNAs are known to play a major role in controlling gene expression and chromatin architecture. We recently showed that RNA is required to open chromatin structure in Drosophila. A potential involvement of RNA in the HMGN5-dependent opening of chromatin has not been studied so far. Here we revealed that HMGN5 has a novel and specific RNA binding activity, which is extended to the HMGN family. HMGN5 is associated preferentially with active regulatory regions and binds co-transcriptionally to the nascent RNA. Additionally, we showed that HMGN5 co-localizes and interacts with CTCF, which suggests a cooperative role of both proteins in organizing higher order structures of chromatin. We showed that HMGN5 forms mutually exclusive complexes with chromatin and RNA in vitro, altogether suggesting a dual role for HMGN5 in gene regulation, switching from nucleosome to RNA binding during gene activation. Overall design: This serie includes CLIP-seq data from cells overexpresiong HMGN5-GFP (3 replicates), and the control cell line overexpressing GFP (2 replicates)